Inhibition of corrosion

ABSTRACT

Corrosion of ferrous metals by corrosive acids at elevated temperatures is inhibited by adding to the corrosive acid a composition comprising effective amounts of at least one acetylenic alcohol, a quaternary ammonium compound and/or an amine, a surfactant, an organic solvent, and a formic acid compound selected from the group consisting of formate esters of the structure:

United States Patent 1 1 1111 79,935

McDougall et a1. Dec. 18, 1973 INHIBITION OF CORROSION [57] ABSTRACT[75] Inventors: Lee A. McDougall; Thomas E. Corrosion of ferrous metalsby corrosive acids at ele- Richards; James R. Looney, all of vatedtemperatures is inhibited by adding to the corro- Houston, Tex. siveacid a composition comprising effective amounts of at least oneacetylenic alcohol. a quaternary ammonium compound and/or an amine, asurfactant. an organic solvent, and a formic acid compound selected [22]Filed: July 12, 1971 from the group consisting of formate esters of the[73] Assignee: Esso Research and Engineering Company, Linden, NJ.

1211 Appl. 196.; 161,994 Structure HCOOR 52 us. 0. 252/149, 252/855 E,252/146, w r R is q qy g p a alkyl g p having 1 252/148, 252/151,252/3901252/391, 252/392 to 6 carbon atoms, cyclo-alkyl residues having5 to 6 51 1111. c1. c1111 7/48, (3231 11/16 carbon atoms, alkenyl and yy g p having 2 I9 [58] Field of Search ..252/146149, 142, 6 Carbon atomsh h may Contain functional group- 252/8.55 E, 388, 390, 392 ingsselected from --C-OH,-OH,=C=O, COOH, SH, and NH and formamides of thestructure:

[56] References Cited UNITED STATES PATENTS R5 2,415,161 2/1947 Camp208/47 H( ()N 2,423,343 7/1947 Plueddemann et a], 252/153 2,449,5859/1948 Camp 208/47 2,799,659 7/1957 Mayhew ct =11. 252/392 2,955,08310/1960 Levin 252/148 x W116: R2 hydrogngroups an alkyl M 252/148 grouphaving 1 to 6 carbon atoms, cyclo-alkyl residues 2 2 14 having 5 to 6carbon atoms, alkenyl and alkynyl 3,514,410 5/1970 Engle et al.....252/146 X groups having 2 to 6 carbon atoms which may contain 3,585,13 91 tanf rd 252/148 X functional groupings selected from C-OH, OH,

3,600,321 8/1971 Tedeschi et al 252/148 COOH, and 3,607,781 9/1971Kaneko et 111 252/148 x 3,107,221 10/1963 Harrison et al 3,231,5071/1966 Beale et al.....

The composition suitably contains a surfactant and an organic solvent.

Primary Examiner-Leon D, Rosdol Assistant ExaminerHarris A. Pitlick 15Claims, N0 Drawings Att0rney-Thomas B. McCulloch et al.

INHIBITION OF CORROSION BACKGROUND OF THE INVENTION 1. Field of theInvention The present invention is directed to inhibition of corrosiveacids. More particularly, the invention is concerned with inhibition ofcorrosive acid in contact with ferrous metals. In its more specificaspects, the invention is concerned with a method and composition forinhibiting corrosion of ferrous metals by corrosive acids in which thecomposition comprises one or more acetylenic alcohols, a quaternaryammonium compound and/or an amine and a formic acid compound having thestructural formula:

HCOOR where R is a phenyl group, an alkyl group having 1 to 6 carbonatoms, cyclo-alkyl residues having to 6 carbon atoms, alkenyl andalkynyl group having 2 to 6 carbon atoms which may contain functionalgroupings selected from C--OH, OH, =C=O, COOH, SH, and NH, andformamides of the structure:

I'ICON where R is hydrogen, phenyl groups, an alkyl group having 1 to 6carbon atoms, cyclo-alkyl residues having 5 to 6 carbon atoms, alkenyland alkynyl groups having 2 to 6 carbon atoms which may containfunctional groupings selected from C-OH, OH, =C=O, COOH, SH, and NH 2.Description of the Prior Art It is known to use formic acid and itscompounds as corrosion inhibitors. It is also known to use one or moreacetylenic alcohols as corrosion inhibitors. The use of amines andvarious nitrogen compounds as corrosion inhibitors is also old in theart. Most corrosion inhibitors have been largely ineffective incombatting the corrosive effects of corrosive acids such as mineralacids, particularly at elevated temperatures.

The use of aziridinyl ester of formic acid as corrosion inhibitors toprevent reaction of aluminum with degreasing solvents has been taught.However, the combi nation of a particular formic acid compound, one ormore acetylenic alcohols and quaternary ammonium compounds such that thecombination is more effective as a corrosion inhibitor than any of itscomponents has not been taught as a corrosion inhibitor for corrosiveacids in contact with ferrous metals.

Prior art considered with respect to this invention includes thefollowing listed US. Pat. Nos.: 2,258,578; 2,415,161; 2,423,343;2,449,585; 2,493,462; 2,799,659; 3,072,460; 3,249,548; 3,338,885;

SUMMARY OF THE INVENTION The present invention may be briefly describedand summarized as involving a corrosion inhibitor composition comprisingeffective amounts of one or more acetylenic alcohols, a quaternaryammonium compound and/or an amine, and a formic acid compound selectedfrom the group consisting of formate esters of the structure:

HCOOR where R is a phenyl group. an alkyl group having 1 to 6 carbonatoms, cyclo-alkyl residues having 5 to 6 car bon atoms, alkenyl andalkynyl groups having 2 to 6 carbon atoms which may contain functionalgroupings selected from C-OH, -OH, =C=O, COOH, SH, and NH and formamidesof the structure:

2 I'ICON where R is hydrogen, a phenyl group, an alkyl group having 1 to6 carbon atoms, cycle-alkyl residues having 5 to 6 carbon atoms, alkenyland alkynyl groups having 2 to 6 carbon atoms which may containfunctional groupings selected from C-OI-I, OH, =C=O, COOH, SH, and NHThe invention also may be summarized as a method of inhibiting thecorrosivity of corrosive acids in contact with ferrous metals, such assteel, by adding to the corrosive acid an effective amount of theaforementiond composition.

VARIABLES OF THE INVENTION The acetylenic alcohols employed in thepresent invention may suitably include ethyl octynol, propargyl alcohol,hexynol and other acetylenic alcohols having the structural formula:

where R; is selected from the group consisting of CH and H and R isselected from the group consisting of hydrogen, alkyl groups having 1 to18 carbon atoms, naphthalyl, phenyl, and alkyl substituted phenylshaving 1 to 10 carbon atoms in the alkyl substituent. Examples of suchalcohols include: methyl butynol, methyl pentynol, hexynol, ethyloctynol, propargyl alcohol, benzyl butynol, naphthalyl butynol, and thelike. Acetylenic alcohols which have 3 to 10 carbon atoms are preferred.

The quaternary ammonium compounds may be illustrated by C-alkylpyridine-N-methyl chloride quaternary, C alkyl pyridine-N-benzylchloride quaternary, quinoline-N'benzyl chloride quaternary,isoquinoline- N-benzyl chloride quaternary, thioalkyl pyridinequaternaries, thioquinoline quaternaries, benzoquinoline quaternaries,thiobenzoquinoline quaternaries, imidazole quaternaries, pyrimidinequaternaries, carbazole quaternaries, the corresponding ammoniumcompounds, pyridines and quinolines may also be used alone or incombination with the quaternary compounds. Thus a pyridine plusquinoline quaternary, a quinoline plus quinoline quaternary, orquinoline or amine alone or in combination may be used.

The formic acid compound may be selected from the esters and amides offormic acid. The formic acid compound may be from the group consistingof formate esters of the structure:

HCOOR where R is a monoaryl group, an alkyl group having 1 to 6 carbonatoms, cyclo-alkyl residues having to 6 carbon atoms, alkenyl andalkynyl groups having 2 to 6 carbon atoms which may contain functionalgroup ings selected from C.OH, OH, =C=O, COOI-l, SI-l, and NH andformamides of the structure:

HCON where R is hydrogen, a phenyl group, an alkyl group having 1 to 6carbon atoms, cycle-alkyl residues having 5 to 6 carbon atoms, alkenyland alkynyl groups having 2 to 6 carbon atoms which may containfunctional groupings selected from --COI-I, OH, =C=O, COOH, SI-l, and NHExamples of the formic acid compound are: methyl formate, ethyl formate,benzyl formate, other alkyl and aryl formates, and the like. Otherexamples include formamide, dimethyl formamide, formanilide, and thelike. Mixtures of the esters and mixtures of the amides may be used.

An alkanol may also be employed in the composition as a solvent asillustrated by methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl,heptyl, octyl and the higher liquid members of these aliphatic alcohols.

Also, a non-ionic surfactant may be used such as as ethoxylated oleatesuch as ethoxylated sorbitol hexaoleate and ethoxylated polyol oleate.Other ethoxylated oleates, tall oils, and other fatty acids may be usedas surfactants. The 8-12 ethylene oxide adduct of tridecyl phenol, nonylphenol, and octyl phenol are preferred surfactants.

Typical amounts of the various components of the composition are shownbelow:

Wt. lst acetylenic alcohol about 3 to about 25 2nd acetylenic alcohol 0to about 10 quaternary ammonium about 5 to about 35 compound and/oramine formic acid compound about 40.0 to about 90.0

alkanol about 0 to about 40.0 (0.! to

about 2.0) surfactant about 0.25 to about 2.0

The essential components of the present invention- DESCRIPTION OF THEPREFERRED EMBODIMENTS AND MODES Formulations including those of thepresent invention were made up as follows:

TABLE I l. 12 percent ethyl octynol 8 percent hexynol 15 percentquinoline-N-benzyl chloride quaternary 1 percent ethoxylated polyololeate 14 percent isopropyl alcohol 50 percent formamide 2. 20 percenthexynol 15 percent quinoline-N-benzyl chloride quaternary 1 percentethoxylated polyol oleate 14 percent isopropyl alcohol 50 percentformamide 3. 5 percent hexynol 5 percent quinoline-N-benzyl chloridequaternary 1 percent ethoxylated octyl phenol (8-10 moles) 89 percentformamide 4. 5 percent hexynol 5 percent quinoline-N-benzyl chloridequaternary 1 percent ethoxylated octyl phenol (8-10 moles) 89 percentdimethyl formamide 5. 5 percent hexynol 5 percent quinoline-N-benzylchloride quaternary 1 percent ethoxylated octyol phenol (8-10 moles) 89percent methyl formate 6. 50 percent standard acid corrosion inhibitor10 percent propargyl alcohol 20 percent ethyl octynol 27 percentquinoline-N-benzyl chloride quaternary 1 percent ethoxylated poyololeate 0.4 percent perfluorated imidazoline 19 percent isopropyl alcohol10 percent pine oil 10 percent oleic acid 2.6 percent ethyl alcohol 50percent formamide 7. percent formamide 8. commercially availableinhibitor with no formic acid derivative which is soluble in organicsolvents. It does however contain acetylenic alcohol(s), amine,surfactant, and organic solvents.

9. 10 percent hexynol 10 percent quinoline-N-benzyl chloride quaternary1 percent ethoxylated octyl phenol (8l0 moles) 79 percent formamide Anyof the acetylenic alcohols may be used in the above formulation butpropargyl alcohol and ethyl octynol and optionally hexynol are preferredalone or in admixture. Likewise the surfactant is preferably the 8-10mole ethoxylated nonyl phenol.

In the oil industry a maximum allowable corrosion rate of about 0.05pounds per square foot of metal exposure is employed for the ferrousmetal (steel) equipment exposed, particularly when acidizing a wellwhere HCL isintroduced into the wall and thence into the formation toremove alkaline deposits or to open channels into the formation. Table Ishows the compositions while the following Tables II and III show theeffect of the compositions on various ferrous metal coupons:

TABLE II Conditions: Pressure: 2000-4000 psig Acid volume/surface ratio:45 ml./in.

Stirring: 40 rpm lnhibitor conc. (ml./ Temperature Exposure 1000 ml.Corrosion PF.) time (hours) HCl Inhibitor acid) Coupon rate (lbs/ft?)200 24 30 (l) 3 P-l05 0.015 3 .l-55 .011 24 30 (2) 3 P-l05 .019 3 N-8O.012 2 (l) 4 .l-55 .042 2 15 (2) 4 .l-55 .043 2 l5 (3) 5 N-SO .017 5.l-55 .008 6 l5 (3) 5 P-105 .029 5 N80 .055 6 1 -105 .025 6 N-80 .028 l15 (3) 5 P-l05 .009 5 N-80 .010 1 15 (4) 8 P-105 .009 8 N-80 .010 2 15(5) 7 P-lOS .036 N-SO .033 2 15 (6) 4 J-55 .043 2 l5 (7) 4 P-l05 1.57 228 (3) 5 N-80 .040 5 .I-55 .029 2 28 114) 2.5 N-BO .345 2.5 .l-55 2.56300 (i 28 (X) 5 li05 1.98 5 N4) 2.72

'01) (i 214 (9) 5 P-l05 .045 5 N-80 .071

tions ofthe present invention practically inhibit all corrosive effectsof the acid.

The amount of the inhibitor composition of the present invention mayvary from about 0.1 percent to about 10 percent by weight based on oneacid or acidic medium. A preferred amount is within the range from about0.5 to about 5 percent by weight.

It will be clear that inhibitor compositions l, 2, 3, 4, 5, 6, and 9mitigate the corrosion of metals in HCL of varying strengths much belowthe acceptable level. It is also clear that inhibitor compositions 7 and8 are over the accepted figure while the inhibitor composi- Theinvention has been described and illustrated by reference to metals as.i-SS, P-l05, and N-80. These are ASTM designations for well knownsteels.

The data show that the particular compositions of the present inventionare unobviously better than the com- .ponents thereof and, therefore,the invention may be quite valuable in combatting corrosion of corrosiveacids such as sulfuric, nitric, hydrochloric, carbonic acid, aceticacid, other organic acids, and the like TABLE 111 against ferrousmetals. Commons: 253 355; i g gg gg The invention may be used in oil andgas fields and Acid voiume/s'urface f 29 Int/in; well environments sinceacid is used in acidizing and Stirling: 45 preventing scale formation byinjection into wells. lt Inhibitor may also be used in other acidenvironments such as in conc. acids used in cleaning ferrous metalequipment such as Tempcra- HCI (ml/ Corrosion We (.F.) Inhibitor ml.acid) Coupon me (lbs-mg.) oil refinery and other equipment asillustrated by heat exchangers of deposited scale, acid soluble salts,and 150 30 (l) 0.5 P 0.0086 50 the like 0 9 The nature and ob ects ofthe resent invention hav- J 55 00 J P 5 (1) .5 P-105 .8006 mg been fullydescribed and illustrated and the best 5:? 1 882 modes and embodimentscontemplated set forth. 150 30 (2) 5 P-105 .0008 What we wish to claimas new and useful and secure $3 8812 55 by Letters Patent is: 150 5 2; 5P 1()5 10004 1. A ferrous metal corrosion inhibiting composition 3? ggi;consisting essentially of corrosion inhibiting effective amounts of:

a. about 3 to about 25 weight percent of at least 1 acetylenic alcoholhaving the structural formula:

where R is selected from the group consisting of CH and H and R isselected from the group consisting of hydrogen, alkyl groups having 1 to18 carbon atoms, naphthyl, phenyl, and alkyl substituted phenyls having1 to 10 carbon atoms in the alkyl substituent;

b. about 5 to about 35 weight percent of an ammonium compound selectedfrom the group consisting of quaternary and unquaternized ammoniumcompounds selected from the group consisting of: C- alkylpyridine-N-methyl chloride quaternary, C- alkyl pyridine-N-benzylchloride quaternary, quinoline-N-benzyl chloride quaternary,isoquinoline-N-benzyl chloride quaternary, thioalkyl pyridinequaternaries, thioquinoline quaternaries, benzoquinoline quaternaries,thiobenzoquinoline quaternaries, imidazole quaternaries, pyrimidinequaternaries, carbazole quaternaries, pyridines and quinolines, andmixtures thereof; and

c. about 40 to about 90 weight percent of a formic acid compoundselected from the group consisting of formate esters of the structure:

HCOOR R: HCON where R is hydrogen, a phenyl group, an alkyl group having1 to 6 carbon atoms, cycle-alkyl residues having 5 to 6 carbon atoms,alkenyl and alkynyl groups having 2 to 6 carbon atoms which areunsubstituted or contain functional groupings selected from COH, =C=O,COOH, -SH, and NH 2. A composition in accordance with claim 1 in whichthe ammonium compound is a quaternary compound.

3. A composition in accordance with claim 1 in which the ammoniumcompound is an amine.

4. A composition in accordance with claim 1 in which the acetylenicalcohol has 3 to 10 carbon atoms.

5. A composition in accordance with claim 1 containing a solventeffective amount up to 40 weight percent of a liquid alkanol,

6. A composition in accordance with claim 5 in which the alkanol isisopropyl alcohol. I

7. A composition in accordance with claim 1 containing a non-ionicsurfactant in an amount from about 0.25 to 2.0 weight percent.

' which the acetylenic alcohol has 3 to 10 carbon atoms.

11. A composition in accordance with claim 1 in which the acetylenicalcohol is a mixture of gthyl octynol, propargyl alcohol and hexynol.

12. A method for inhibiting the corrosivity ofa corrosive acid incontact with a ferrous metal at elevated temperatures which comprisesadding to said corrosive acid an inhibiting amount of a ferrous metalcorrosion inhibiting composition consisting essentially of corrosioninhibiting effective amounts of:

a. about 3 to about 25 weight percent of at least 1 acetylenic alcoholhaving the structural formula:

where R is selected from the group consisting of CH and H and R isselected from the group consisting of hydrogen, alkyl groups having 1 to18 carbon atoms, naphthalyl, phenyl, and alkyl substituted phenylshaving 1 to 10 carbon atoms in the alkyl substituent;

,b. about 5 to about 35 weight percent of an ammonium compound selectedfrom the group consisting of quaternary and unquaternized ammoniumcompounds selected from the group consisting of: C- alkylpyridine-N-methyl chloride quaternary, C- alkyl pyridine-N-benzylchloride quaternary, quinoline-N-benzyl chloride quaternary,isoquinoline-N-benzyl chloride quaternary, thioalkyl pyridinequaternaries, thioquinoline quaternaries, benzoquinoline quaternaries,thiobenzoquinoline quaternaries, imidazole quaternaries, pyrimidinequaternaries, carbazole quaternaries, pyridines and quinolines, andmixtures thereof; and

0, about 40 to about weight percent of a formic acid compound selectedfrom the group consisting of formate esters of the structure:

HCOOR where R is a phenyl group, alkyl group having 1 to 6 carbon atoms,cyclo-alkyl residues having 5 to 6 carbon atoms, alkenyl and alkynylgroups having 2 to 6 carbon atoms which are unsubstituted or containfunctional groupings selected from -COH, OH, =C=O, COOH, SH, and NH andformamides of the structure:

2 HCON where R is hydrogen, a phenyl group, an alkyl group having 1 to 6carbon atoms, cyclo-alkyl residues having 5 to 6 carbon atoms, alkenyland alkynyl groups having 2 to 6 carbon atoms which are unsubstituted orcontain 0.25 percent to about 10.0 percent by volume based on thecorrosive acid.

15. A method in accordance with claim 12 in which 14. A method inaccordance with claim 12 in which 5 the ferrous metal is steeltheinhibiting amount is within the range from about

2. A composition in accordance with claim 1 in which the ammoniumcompound is a quaternary compound.
 3. A composition in accordance withclaim 1 in which the ammonium compound is an amine.
 4. A composition inaccordance with claim 1 in which the acetylenic alcohol has 3 to 10carbon atoms.
 5. A composition in accordance with claim 1 containing asolvent effective amount up to 40 weight percent of a liquid alkanol. 6.A composition in accordance with claim 5 in which the alkanol isisopropyl alcohol.
 7. A composition in accordance with claim 1containing a non-ionic surfactant in an amount from about 0.25 to 2.0weight percent.
 8. A composition in accordance with claim 7 in which thesurfactant is an 8 to 12 mole polyoxyethylene adduct of nonyl phenol. 9.A composition in accordance with claim 7 in which the surfactant is an 8to 12 mole ethylene oxide adduct of an alkyl phenol having 8 to 20carbon atoms in the alkyl group.
 10. A composition in accordance withclaim 9 in which the acetylenic alcohol has 3 to 10 carbon atoms.
 11. Acomposition in accordance with claim 1 in which the acetylenic alcoholis a mixture of ethyl octynol, propargyl alcohol and hexynol.
 12. Amethod for inhibiting the corrosivity of a corrosive acid in contactwith a ferrous metal at elevated temperatures which comprises adding tosaid corrosive acid an inhibiting amount of a ferrous metal corrosioninhibiting composition consisting essentially of corrosion inhibitingeffective amounts of: a. about 3 to about 25 weight percent of at least1 acetylenic alcohol having the structural formula:
 13. A method inaccordance with claim 12 in which the corrosive acid is hydrochloricacid.
 14. A method in accordance with claim 12 in which the inhibitingamount is within the range from about 0.25 percent to about 10.0 percentby volume based on the corrosive acid.
 15. A method in accordance withclaim 12 in which the ferrous metal is steel.